In the last contest, which I couldn't take part, two users cheated. .eray and Lutfu submitted almost exactly the same code for problem B. I put the photos and links.
submission of .eray: https://codeforces.me/contest/1354/submission/80463880
submission of Lutfu: https://codeforces.me/contest/1354/submission/80509151
This things shouldn't happen.